What is the torque for spark plugs?

[DiHeidi]

Spark plug torque is 20-30 Nm. Spark plugs of different sizes require different tightening forces. For example, 12mm spark plugs generally require a torque of 20-25 Nm, while 14mm spark plugs need 25-30 Nm for proper tightening. Spark plugs are crucial components in gasoline engine ignition systems. They introduce high voltage into the combustion chamber and generate sparks by jumping the electrode gap, thereby igniting the air-fuel mixture in the cylinder. Under high voltage, the air between the spark plug's center electrode and side electrode rapidly ionizes, forming positively charged ions and negatively charged free electrons. When the voltage reaches a certain threshold, the number of ions and electrons increases avalanche-like, causing the air to lose insulation properties and creating a discharge channel - a phenomenon called "breakdown". At this moment, the gas forms a luminous body known as a "spark". Accompanied by thermal expansion, a "crackling" sound occurs. These electrical sparks can reach temperatures of 2000-3000°C, sufficient to ignite the air-fuel mixture in the combustion chamber.